1. Field of the Invention
This invention relates generally to electrical connectors, and pertains more particularly to adapters for determining the polarization of connectors.
2. Description of the Prior Art
The need for indexing or polarizing electrical connectors has been recognized for some time. Obviously, the mismating of a plug component with the wrong receptacle component can in a number of situations prove disastrous. The problem is particularly acute in aeronautical and aerospace installations where electrical connectors must frequently be coupled together in confined spaces where the operator must reach through small access openings and cannot see what he is doing.
In the type of installation alluded to above, it becomes readily apparent that a color coding system is completely ineffectual because the operator is unable to see the connector components. One solution to the problem is for the manufacturer to provide various plug and receptacle components that have a sufficient number of different key and keyway configurations permanently embodied therein so that only those components with the same key and keyway patterns can be coupled together. However, this necessitates the stocking of relatively large numbers of male and female components that are physically identical other than for their key and keyway patterns.
Furthermore, the reliance on built-in different key and keyway patterns increases the cost of manufacturing such electrical connectors because different tooling is required for each different pattern. Also, the cataloging and inventorying of a large number of connectors proves troublesome and expensive.
Still further, the installer or connector user must have the proper number of differently indexed connectors at the job site and must plan ahead so that he is certain that he is wiring the correct male component for use with the proper female component. In other words, if the installer inadvertently wired one plug component into a first circuit and then by mistake selected the wrong receptacle component and wired it into a second circuit to be connected to the first circuit, he would have to rewire one or the other just to obtain a compatible keying pattern, for he would not be able to change either built-in pattern.
Because of the stockpiling and concomitant difficulties experienced with predesigned keying patterns which cannot be modified, efforts have been made in the past to provide connectors possessing keying patterns that could be altered. For instance, U.S. Pat. No. 3,287,031 granted to Simmons et al for an "Indexed Key Connection" makes use of removable plugs. This requires a number of slots in both the male and female components, plugs being inserted into selected slots so that only the components with the same plug insertions can be mated together. In a somewhat similar vein, U.S. Pat. No. 3,614,711 issued to Henderson et al for "Electrical Connector Having Adjustable Keying" employs grooves in which plugs can be removed to provide a keyway and metal prongs that can be bent to provide keys receivable in those keyways from which the plugs have been removed. Not only is the cost of manufacturing connectors of the foregoing categories more expensive, but it is a bother to add and remove plugs. Furthermore, especially since not too many keying arrangements are possible, one could inadvertently adopt the same pattern for two connectors without recognizing it, thereby permitting mismating of components.
U.S. Pat. No. 3,097,905 granted to Shearer et al for "Indexable Key Connector" teaches the use of an adapter but such an arrangement permits only one component to be modified for use with a component having a fixed keyway pattern. Furthermore, the connector must be specially designed so as to accommodate the adapter, the connector shell belonging to one of the components requiring notches which must correspond in number and spacing to inwardly directed lugs on the adapter. Still further, a locking nut is required.
Consequently, the patented construction just referred to is unduly complex and costly. Still further, it does not have the degree of versatility as far as rendering various male and female components mateable. In other words, the arrangement described in the patent does not allow standard components to be indexed or polarized.